PHILADELPHIA – Jordan Matthews wouldn't divulge the extent of his knee injury that kept him out of the last three weeks of spring organized team activities and had him listed as "limited" for the start of training camp.

But Matthews, the Eagles' top wide receiver the last two seasons, did say that the knee has bothered him since he got hit there last summer in training camp, and that he wanted to let it heal "naturally" rather than have surgery, knowing he had a full offseason to recover.

The knee still seems to be an issue, even though Matthews was a full participant Thursday in the Eagles' first full-squad practice of training camp. That led to speculation that the injury was more serious than tendinitis, the term Eagles coach Doug Pederson used during the spring.

"I hate putting a specific word on it because then people say, 'Oh, I’ve played with that before,'" Matthews said. "Trust me, if I could be out here and play, I’d be out here playing and I’d be out here practicing. That should never be a question about me. When it comes to playing, I’m always going to come out here and go to work. I don’t like to put a word on it, but it’s definitely something that I had to monitor, and something I had to get better at."

When the injury first happened last summer, the Eagles called it a bone bruise and Matthews missed all four preseason games. He missed two games later in the season with an ankle injury, which he said set him back further in fully recovering from the knee injury.

But eyebrows were raised when the knee was still an issue during the OTAs in May and June. Matthews was asked Thursday if surgery was an option after suffering the initial injury last summer.

"I think that's always the initial thing people always want to ask whenever something significant happens like that," Matthews said. "You just make a choice. You say I either want to do it naturally or you want to go that route because, to be honest, surgery is a lot more common than people think in the NFL ... I went the natural route because working with our team doctors, working with our trainers, praying every night, it has gotten better.

"I feel progressively that I'm going to feel better every single day. Soon, I feel like I'm going to be 100 percent ... I'm confident and just excited about the future."

Matthews showed that Thursday by making a leaping catch over a defender deep down the field during a 7-on-7 drill. Then again, Matthews admitted that he wasn't sure how his knee would react to making a catch like that.

"There's always that apprehension," Matthews said. "But once you come out here, it's football ... It's definitely something that can be in your mind."

There is a full training camp ahead, and that includes three planned days of live hitting and four preseason games. Matthews didn't know if he'll be held back on those occasions.

"Once I hit this field, I’m going to tell you that I’m great," Matthews said. "I’m just going to speak positively and I’m going to come out here and work hard. I’m going to do what I’ve always done — do my rehab protocol, make sure I’m always getting the proper amount of rest, acupuncture, massage, all that stuff. To be honest, I’m going to be optimistic that’s not going to be a long-term deal and that I’ll be good to go as camp goes on."

Still, it's a tricky situation for Matthews. He's in the final year of his rookie contract and is due to earn $1.1 million. Typically, the Eagles have given extensions to promising young players a year before free agency.

Matthews, who turned 25 earlier this month, would certainly qualify as one of those players. He has been the Eagles' leading wide receiver in each of the past two seasons, with 85 catches for 997 yards in 2015 and 73 for 804 yards in 14 games last season.

He's one of five players in NFL history with at least 65 receptions and 800 yards in each of his their first three seasons — Odell Beckham Jr., Mike Evans, A.J. Green and Randy Moss are the others.

But Matthews denied a report that he sat out the final three weeks of the OTAs in part because of his contract situation.

"I would literally never do that," Matthews said. "If you guys know me any from the time that I’ve been here, I go to work ... So I would never sit out to try to force somebody’s hand. That’s just not me. I’m going to come out here and go to work. I wasn’t able to [in the spring]. That’s just the breaks. I’m out here now, ready to go."